1. Field of the Invention
The invention relates to a cable drum comprising a substantially cylindrical drum body having drum walls arranged on its axial ends, and comprising a groove arrangement provided on the drum body which has at least one parallel area in which grooves extend parallel to the circumferential direction of the drum body and at least one incline area in which grooves are slanted about an angle relative to the circumferential direction of the cylindrical drum. All grooves in the parallel areas have the same groove width.
2. Description of the Related Art
From patent document GB 776,007 a cylindrical cable drum is known which has two areas with oppositely positioned grooves on its periphery, wherein the grooves are displaced relative to one another in the axial direction and have a length which is less than one half of the circumference.
Patent documents JP 09156887 A and JP 11263592 A disclose cable drums which have on both ends screw-shaped grooves with opposite orientation so that a cable is wound in axially opposite directions on both drum sides so that axial forces on the cable drum are reduced.
Patent document WO 86/01189 discloses a cable winding device with a cylindrical drum wherein the drum has first circumferential grooves at least about a portion of its periphery for receiving the innermost cable layer. Moreover, second grooves are provided which have a reduced diameter in comparison to the first grooves and which are capable of receiving an end strand which is connected to the innermost end of the cable but has a correspondingly reduced diameter. The second grooves are formed such in the base of the first grooves that the innermost cable layer is progressively unwound from the first end of the drum to the oppositely positioned second end and the end strand, after unwinding of the cable, is unwound progressively from the second end to the first end of the drum.
The invention has the object to provide a cable drum of the aforementioned kind with which a cable can be wound onto the drum in the clockwise direction as well as in a direction opposite thereto.
This object is solved by a cable drum of the aforementioned kind having grooves which cross one another the incline area.
The grooves which are crossing one another in the incline areas enable that a cable can be wound onto the drum in the clockwise direction as well as in a counter-clockwise direction. In this way, it is not necessary to provide different cable drums for different winding directions, as has been the case in the past. The cable drums according to the invention can be employed significantly more universally.
According to one embodiment of the invention, it is suggested that the pitch, i.e., the displacement of neighboring grooves in the longitudinal direction, matches approximately 1 to 1.1 times the diameter of the cable to be wound and that the grooves that are positioned adjacent to one another in the longitudinal direction of the cable drum contact one another. In this connection it is expedient that on the drum body two parallel areas and two incline areas are arranged. In this case, the parallel areas can have an axial displacement relative to one another which corresponds to half the pitch. In this way, for one winding of the cable about the drum a displacement is achieved which corresponds to 1 to 1.1 times the diameter of the cable so that the cable is wound tightly onto the drum. In an especially advantageous embodiment, the incline areas cover overall approximately 20% to 30% of the outer surface area of the drum body.
Moreover, in order to achieve a uniform winding action, it can be provided that in the parallel area filler wedges are arranged on one drum wall which prevent that a cable winding of the second cable layer wound at the drum wall is wound so as to have a diameter which is smaller than that of the second cable layer. A further embodiment of the invention provides that on a second drum wall a ramp wedge is provided which lifts the cable from a first cable layer onto a second cable layer.